Underground addon - Gears of War

Years ago, the Locust Horde gathered under every major city and launched a surprise attack. Untold numbers died on Emergence Day, and rather than allow the Locust to keep the spoils of their aggression, humans used chemical weapons and orbital particle beams to destroy them - and their own cities. With most urban centers and military installations rubble, survivors gathered on Jacinto Plateau, whose solid granite strata could not be easily penetrated. When the Horde breached the plateau's defenses, Marcus Fenix defied orders to save his father at East Barricade Academy - but he was too late. Charged with dereliction of duty, he has been sentenced to 40 years in Jacinto Maximum Security Penitentiary...